Colleen Garrigan does some wonderfully artistic or even wacky assemblages of old tools, architectural salvage etc.
Roy has developed a sophisticated take on the art of putting together native and non-native perennials - all explained in a neat little book - 'Small Perennial Gardens: The Know Maintenance Approach'. The pun is based on the fact that what so many (American) gardeners seem to want is NO maintenance, but Roy is keen to stress that if you KNOW your plants then you can reduce maintenance - and this is key, without smothering the ground with wood chip mulch. 
The plant combinations are very much about creating a complete canopy so grasses shoehorn in between flowering forbs like liatris and echinacea and sprawly (but not actualy spreading) low things like calaminthas can fill in the gaps. The display gardens around the nursery are very accomplished with a good 'field' type effect, and nicely integrated with shrubs and small trees.
Now - the wood chip. A good example of how a 'good thing' becomes a 'bad thing'. Not so long ago mulch was seen as solving a lot problems - like reducing moisture loss and smothering weeds, but of course like all good things (chocolate cake, beer etc.) can be overdone. Wood chip has become one of Roy's pet hates, and I can see why - a lot of folk around Chicago seem to think that wood chip is an end in itself, any plants standing out looking rather lonesome. The stuff is dumped on every year, so not surprisingly plants underneath can be completly buried, and in the hot humid summers, all sort of diseases get going. What's more, a lot of the wood chip gets shipped up from Georgia, so the transport miles are pretty crazy.
